Smart, cool, brave, steady but with a spark and a wicked sense of humour. She doesn't suffer fools and she intrinsically knows herself.

Heather Peace as DS Sam Murray

In series two of Lip Service I was given some real challenges with the writing.

I felt like I had a real sense of who Sam was, which was a blessing as the writing explores how this steady character would react if everything around her became out of control.

It explores how it affects her work and it looks at Sam dealing with the issues alone and not asking for help.

I think the love triangle between Cat, Sam and Frankie only worked in series one because of the writing.

Harriet Braun (series writer and creator) wanted the Sam character to be a real contender in the fight for Cat's affection.

This contributes to the drama as it leaves the audience torn between Sam and Frankie.

When I first auditioned for Lip Service it was for the part of Frankie - they hadn't yet started to look for a Sam.

I read for the part but just wasn't right and I knew it. I couldn't find anything charming or loveable about the character but I think Ruta Gedmintas did.

At the end of my audition for Frankie I said "I could play that Sam character standing on my head!" at which point they made me read for it there and then.

I was thinking "I better get this right now after being so blooming cocky!".

At that time she was only in a couple of scenes and when I came out of the audition I phoned my agent and said "If I stood a chance of getting the lead role in Lip Service, I just talked my way out of it by reading for one of the really minor roles, sorry".

Cat (Laura Fraser) and girlfriend Sam (Heather Peace) in Rubies bar

The hardest part of this second series was the fact that I had a few scenes on my own to film and I tend to be someone who bounces off the energy of the other people in the scenes with me.

I have the concentration span of a hamster so I really had to stay in the zone.

I listened to my iPod between shots so that I didn't start chatting and being silly.

It was a challenge but one that I loved every minute of.

I believe in the show and the writing... so roll on series three (fingers crossed).

Heather Peace plays the role of Detective Sergeant Sam Murray in Lip Service.

Comments made by writers on the BBC TV blog are their own opinions and not necessarily those of the BBC.